Trimetallic Co–Ni–Mo Nanoparticles on Carbon Dots Boost Hydrogen Fuel Production

Hydrogen has long been heralded as the clean fuel of the future, yet one stubborn problem continues to hold it back: how to store and release it safely, cheaply, and on demand. Compressed gas tanks and cryogenic liquids demand heavy infrastructure and raise safety concerns, especially for portable and mobile applications. A research team from Mansoura University and Mansoura National University in Egypt, working with colleagues at Jazan University in Saudi Arabia, now reports a catalyst that could make a chemical hydrogen-storage route dramatically more practical. Writing in the journal Catalysis Letters, the researchers describe ultrasmall cobalt–nickel–molybdenum nanoparticles anchored on nitrogen-doped carbon quantum dots that release hydrogen from sodium borohydride solutions with remarkable speed, using abundant, inexpensive metals instead of precious platinum-group catalysts.

The chemistry at the heart of the study is hydrolysis of sodium borohydride, a white crystalline solid that packs hydrogen densely and remains stable in alkaline solution until a catalyst triggers its breakdown. When borohydride ions encounter the right catalytic surface in water, they react to yield four molecules of hydrogen gas per borohydride ion, leaving only sodium metaborate as a byproduct. The reaction is exothermic and controllable, producing hydrogen only when the fuel solution meets the catalyst, which makes it attractive for feeding proton exchange membrane fuel cells in portable devices, drones, and backup power systems. The obstacle has always been catalytic cost and durability. Noble metals perform superbly but are far too expensive for mass deployment, while cheaper cobalt-based catalysts often suffer from sluggish kinetics, agglomeration, and deactivation.

The Egyptian and Saudi team attacked this problem by combining two design strategies that catalyst scientists have pursued largely in parallel: trimetallic synergy and nanoscale carbon support engineering. Rather than relying on a single active metal, they alloyed cobalt, nickel, and molybdenum together in varying proportions, reasoning that the proximity of three different transition metals would modify each other’s electronic structure and create a richer landscape of active sites for breaking boron–hydrogen bonds. Molybdenum, added in small amounts, acts as an electronic promoter, while cobalt provides the primary hydrolysis activity and nickel contributes additional dehydrogenation capability. Previous work on bimetallic cobalt–nickel systems had hinted at such cooperative effects, but the systematic three-metal optimization carried out here goes considerably further.

The supporting material is just as important as the metal particles themselves. Carbon quantum dots are nanometer-scale carbon clusters decorated with surface functional groups, known for excellent electrical conductivity, chemical stability, and strong interactions with anchored metals. By using nitrogen-doped carbon quantum dots as the matrix, the researchers gave the metallic nanoparticles a conductive, defect-rich platform that both prevents them from clumping and facilitates the electron transfer steps involved in activating the borohydride ion. The synthesis itself is elegant in its simplicity: a hydrothermal-assisted chemical reduction strategy converts metal salts into ultrasmall alloy nanoparticles directly on the carbon dots, without requiring exotic precursors or elaborate equipment, an important consideration for any future scale-up.

Systematic composition screening across mono-, bi-, and trimetallic formulations identified a clear winner. The Co70Ni25Mo5 composition, roughly seventy parts cobalt, twenty-five parts nickel, and five parts molybdenum, outperformed every other ratio tested. Structural characterization by X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy confirmed that the optimized catalyst consists of ultrasmall metallic nanoparticles averaging just 6.12 nanometers in diameter, with a tight size distribution of about one nanometer, spread uniformly across the carbon quantum dot support. Critically, the imaging and diffraction data revealed no detectable phase segregation, meaning the three metals genuinely mixed into intimate alloyed particles rather than forming separate cobalt, nickel, and molybdenum domains. That intimate mixing is precisely what enables the electronic synergy the team was seeking.

The performance figures are striking. At a catalyst loading of only 100 milligrams per liter, the optimized Co70Ni25Mo5@CQDs catalyst released the full theoretical hydrogen yield of 162 milliliters from the borohydride solution within just 15 minutes. Expressed as a hydrogen generation rate, that corresponds to 7,000 milliliters of hydrogen per gram of catalyst per minute, a figure that places this earth-abundant catalyst in the same conversation as far costlier noble-metal systems. For a portable fuel cell application, where a compact cartridge of sodium borohydride solution and a small amount of catalyst could power a device for hours, that combination of rate and metal affordability is exactly what the field has been looking for.

Kinetic analysis added a mechanistic dimension to the performance story. By varying catalyst concentration while holding everything else constant, the researchers measured a reaction order of approximately 1.03 with respect to catalyst loading, indicating that the reaction rate scales almost perfectly linearly with the amount of available active surface. In contrast, the reaction order with respect to sodium borohydride concentration came out at a fractional 0.31. This asymmetry tells a clear mechanistic tale: the borohydride ions saturate the catalyst surface rapidly, so the overall rate becomes governed by the surface reaction itself rather than by how much fuel is dissolved in solution. A surface-controlled mechanism of this kind is highly desirable in practical generators, because it means hydrogen output can be tuned predictably simply by metering the catalyst, without sensitivity to fluctuations in fuel concentration.

Temperature-dependent measurements reinforced the picture of unusually favorable kinetics. The apparent activation energy came out at just 9.04 kilojoules per mole, with an uncertainty of 0.87, among the lowest values reported for transition-metal-catalyzed borohydride hydrolysis. In plain terms, the energy barrier the reactants must surmount on the catalytic surface is very small, which explains why hydrogen evolution proceeds briskly even near ambient conditions. The authors attribute this low barrier and the overall exceptional activity to two intertwined factors: the synergistic electronic interaction among cobalt, nickel, and molybdenum species, which optimizes the adsorption and activation of borohydride and water on the surface, and the outstanding dispersion and electron-transfer properties of the nitrogen-doped carbon quantum dot support, which keeps every nanoparticle small, accessible, and electrically wired to its neighbors.

Durability, the perennial weakness of nanoscale catalysts, was also addressed. The optimized catalyst maintained acceptable catalytic stability over six consecutive hydrolysis cycles, retaining useful activity despite the inevitable leaching and surface restructuring that plague metal nanoparticles in aqueous reactive environments. While six cycles is far from the thousands demanded of commercial systems, the result demonstrates that the carbon quantum dot anchoring strategy provides genuine resistance to agglomeration, and it gives the researchers a clear baseline for further improvement through support engineering and reaction-condition optimization.

The broader significance of the work lies in its demonstration that carefully orchestrated combinations of cheap metals, rather than expensive platinum or ruthenium, can deliver the fast, controllable hydrogen release that chemical hydride storage demands. Sodium borohydride hydrolysis fits neatly into a future hydrogen economy as a complementary technology: where pipelines and large electrolyzers serve stationary infrastructure, catalytic hydrolysis cartridges can serve the portable and mobile niche, delivering fuel-cell-grade hydrogen at the twist of a valve. The authors note no competing interests and report that the research received no external funding. If subsequent work can extend the catalyst’s cycle life while preserving its remarkable 7,000-milliliter-per-gram-per-minute output, the humble trio of cobalt, nickel, and molybdenum sitting on carbon quantum dots may well find itself at the heart of the next generation of on-demand hydrogen generators.

Subject of Research: Trimetallic Co-Ni-Mo nanoparticles supported on carbon quantum dots for catalytic hydrogen generation via sodium borohydride hydrolysis

Article Title: Efficient Trimetallic Co–Ni–Mo Nanoparticles Anchored on Carbon Quantum Dots for Efficient Hydrogen Generation via Sodium Borohydride Hydrolysis

Article References: Abd-elaal, A. M., Yousef, A., Abdelsalam, M. M., Rashed, I. G., & El-Halwany, M. M. (2026). Efficient Trimetallic Co–Ni–Mo Nanoparticles Anchored on Carbon Quantum Dots for Efficient Hydrogen Generation via Sodium Borohydride Hydrolysis. Catalysis Letters, 156(10), Article 281. https://doi.org/10.1007/s10562-026-05491-5

Image Credits: AI Generated

DOI: 10.1007/s10562-026-05491-5

Keywords: hydrogen generation, sodium borohydride hydrolysis, trimetallic nanocatalyst, carbon quantum dots, cobalt nickel molybdenum, nanoparticles, catalysis, hydrogen storage, reaction kinetics, activation energy, chemical hydride, fuel cells